The present invention relates to a low air pressure tire for all terrain vehicles, in which weight reduction is achieved with maintaining or improving its shock absorbing and damping characteristics.
In general, tires for all terrain vehicles (the so called ATV) for running on all terrain like gravel roads, sandy roads, muddy roads and rough roads, are required to have a good shock absorbing characteristic and a good vibration damping characteristic because shocks during running are especially hard.
In addition, such a kind of vehicle is often equipped with no suspension mechanism.
It is therefore, necessary for the tire itself to have functions of both suspension mechanism and shock absorber.
For that, there was proposed for example Japanese Patent Applicaiton laid open No.60-234008, wherein to absorb and alleviate shocks, the longitudinal spring coefficient of the tire is lowered by selecting the rubber thickness of a sub-tread part of the tire body under tread grooves, the angle of carcass cords and the material of the carcass cords, which all have much effect on the above-mentioned characteristics. The tire comprises a tire main body of which the rigidity is gradually increased toward tire bead parts from a tire crown part and a tread rubber disposed on the crown part.
Although this tire has functions of absorbing and alleviating shocks, the rubber thickness is increased from the crown part to the bead part causing an increase in tire weight.